Time Calculator
Add or subtract days, hours, minutes, and seconds from any clock time.
CalculatorHow to use this tool
Add or subtract days, hours, minutes, and seconds from a clock time. The result shows both 12-hour and 24-hour time and clearly marks when the calculation crosses into another day.
- STEP 1Enter the starting clock time.
- STEP 2Select whether to add or subtract the duration.
- STEP 3Enter any combination of days, hours, minutes, and seconds, then calculate.
Time arithmetic works by converting every value to seconds, applying the addition or subtraction, and wrapping the final clock time across 24-hour boundaries.
All inputs and calculations stay in your browser; TimeKit does not send your entries to a server.
Examples
Frequently asked questions
Can I add more than 24 hours?
Yes. Enter any number of days or hours; the calendar-shift result tells you how many days later or earlier the answer falls.
What is the difference between this and the duration calculator?
This calculator changes a clock time by a duration. The duration calculator measures the elapsed time between two clock times.